The effect of atom motion in Rydberg-atom quantum spin models

Ultracold Rydberg atoms in optical lattices and tweezers can realize quantum spin models. Recent experiments on one such system [1] have revealed dynamics not fully explained by coherent numerical calculations, pointing towards atom motion as a source of these deviations. In this talk, we show that atom motion indeed can semi-quantitatively explain the experimentally observed behavior. We study the effect of motion during quenches and ramps of 2D Rydberg atom systems nominally described by Ising models. As the motional degrees of freedom make it hard to solve the system with exact diagonalization or similar techniques, we employ the discrete truncated Wigner approximation (dTWA). Our results reveal that motional effects accumulate on timescales comparable to the interaction timescale in Ref. [1], suppressing correlation growth. Our results semi-quantitatively agree, without fitting, with Ref. [1]’s phenomenologically-proposed and experimentally-fit two-body interaction noise model. We discuss how this atomic motion will depend on atom species, lattice depth, Rydberg principal quantum number, and other important experimental variables.

[1] Guardado-Sanchez et al. Phys. Rev. X 8, 021069 (2018)